Upon meeting a young boy named Seita who makes a living as a pickpocket, Gintoki discovers that he is pickpocketing out of a desire to meet his long-lost mother, Hinowa, Yoshiwara's number one courtesan. Gintoki and his friends venture to Yoshiwara to fulfill Seita's wish, but standing in their way is Housen, the Night King who rules Yoshiwara.

The silver-haired samurai Sakata Gintoki investigates the disappearance of a legendary sword named Benizakura while his partners Kagura and Shimura Shinpachi try to find out what has happened to Gintoki's friend, Kotaro Katsura.

In an era where aliens have invaded and conquered feudal Tokyo, a young samurai seeks work as he can.